Sucralose is a product using sucrose as a raw material, in which three hydroxies are selectively substituted with chlorine. It has 600 times sweetness more than a granulated sugar, and the taste is similar to the granulated sugar, and it has the characteristic of great stability in respect of heat and pH. Since 1976, when it was discovered in a cooperated research of UK company Tate & Lyl with a university, it has been introduced and popular in many countries.
The method of synthesizing sucralose mainly comprises two kinds, that is, hologroup protected synthesis and monoesterification, wherein the latter one is more widely used to synthesize sucralose. Therefore synthesis of sucrose-6-acetic ester, which is a crucial intermediate when synthesizing sucralose utilizing the method of monoesterification, is always concerned. U.S. Pat. No. 6,939,962 disclosed a method for synthesizing sucralose, which achieves an ideal result by using acetic anhydride as an acetylation reagent, and under catalysis of organotin, using cyclohexane as an azeotropic dehydration reagent. However, this method has high cost, and the operation is complex and the raw materials are difficult to buy. Moreover, U.S. Pat. No. 5,449,772, European patent EP0515145 also disclosed another method of synthesizing sucrose-6-acetic ester, which get a cyclized intermediate through a reaction of sucrose and Trimethyl orthoacetate, and then the cyclized intermediate is hydrolyzed to generate a composition of sucrose-6-acetic ester and sucrose-4-acetic, and then a portion of sucrose-4-acetic is converted sucrose-6-acetic ester by using tert-butylamine as a converter. This method is simple on operation, and the reaction is mild, but the selectivity of acylation is poor. Moreover, other patents also disclosed the method of synthesizing sucrose-6-acetic ester, such as U.S. Pat. No. 5,440,026 using ketene acetal as a acylating agent, Japanese patent JP2211888 using enzyme catalysis, Chinese patent CN1827628 using electrolytic process and CN1453285 using solid sulphate as a catalyst. All of these methods have the disadvantages of poor selectivity or low conversion rate.